Serologic evaluation of viral hepatitis

X protein of hepatitis B virus modulates cytokine and growth factor related signal transduction pathways during the course of viral infections and hepatocarcinogenesis

Hepatitis B virus produces chronic infections of the liver leading to cirrhosis and hepatocellular carcinoma. The X protein of hepatitis B virus (HBx) is a multifunctional protein that can interact with p53 but can also influence a variety of signal transduction pathways within the cell. In most instances this small viral protein favors cell survival and probably initiates hepatocarcinogenesis. HBx upregulates the activity of a number of transcription factors including NF-kappa B, AP-1, CREB, and TBP. However, the majority of HBx is localized to the cytoplasm where it interacts with and stimulates protein kinases such as protein kinase C, Janus kinase/STAT, IKK, PI-3-K, stress-activated protein kinase/Jun N-terminal kinase, and protein kinase B/Akt. This small viral protein can localize to the mitochondrion. HBx may act as an adaptor or kinase activator to influence signal transduction pathways. This review will attempt to analyze the involvement of HBx in signal transduction pathways during hepatitis B viral infections and hepatocellular carcinoma development.

[Incidence hepatitis C virus seroconversion after the implementation of a prevention and control program at a hemodialysis unit]

This study aimed at reporting the incidence of the hepatitis C virus as well as the prevention and control measures adopted in an hemodialysis unit. It is a prospective study developed with patients attended from September 1996 to December 1998 in an hemodialysis unit. The consultations from September 1996 to December 1996 were considered the control group and the ones from January 1997 to December 1998 the intervention group. Regarding the period of the control group, the routine of the unit was organized based on the regulation 2042 that systematizes the services of renal therapy. In the subsequent period, complementary measures were implemented. From 1997 to 1998, authors observed the reduction in the number of cases of hepatitis C.

Factors influencing the immune response to hepatitis B vaccine, booster dose guidelines, and vaccine protocol recommendations

The clinical course and immunodiagnosis of hepatitis B infection is discussed. Immunization is necessary to prevent the clinical disease, the development of carriers, and the transmission of the hepatitis B virus to susceptible persons. Host factors that can curtail the immune response include increasing age, obesity, smoking cigarettes, and having a medical condition that compromises the immune system. Increasing the dose of vaccine, administering the inoculations intramuscularly, and giving the vaccine more frequently can enhance the immune response. The duration of immunity following vaccination has not yet been defined, but booster dose guidelines for selected groups are provided. Finally, recommendations for developing and implementing hepatitis B immunization protocols are presented.

Human hepatitis delta antigen is a nuclear phosphoprotein with RNA-binding activity

The genetic origin, structure, and biochemical properties of the delta antigen (HDAg) of a human hepatitis delta virus (HDV) were investigated. A cDNA fragment containing the open reading frame encoding the HDAg was transcribed into RNA and used for in vitro translation in rabbit reticulocyte lysates. The HDAg open reading frame was also inserted into an expression vector containing a simian virus 40 T-antigen promoter and expressed into COS 7 cells. In both systems, a protein species of 26 kilodaltons was synthesized from this open reading frame and could be specifically immunoprecipitated with antisera obtained from patients with delta hepatitis. A similar protein was also synthesized from antigenomic-sense monomeric HDV RNA in both systems, although the efficiency of translation was lower than that of the isolated open reading frame. This protein was found to be phosphorylated at the serine residues. Immunoperoxidase studies with anti-HDV sera demonstrated that the HDAg was expressed mainly in the nuclei of the transfected COS 7 cells. Moreover, the HDAg was shown to bind the genomic RNA of HDV. These studies indicate that HDAg is encoded by the antigenomic-sense RNA of HDV and is a nuclear phosphoprotein associated with an RNA-binding activity.

Hepatitis B serology--help in interpretation

This review discusses the serologic markers of hepatitis B virus (HBV) infection. Interpretation of various serologic profiles is provided, and the importance of maternal screening for interruption of perinatal transmission of HBV infection is stressed.

Molecular cloning and sequencing of a human hepatitis delta (delta) virus RNA

Human hepatitis delta (delta) virus (HDV) is a form of defective virus, which infects humans only in the presence of a co-infecting hepatitis B virus (HBV). HDV superinfection in a chronic HBV carrier often results in severe chronic hepatitis and cirrhosis, whereas acute HDV and HBV co-infection is frequently associated with fulminant hepatitis. HDV consists of a 36-nm particle, which contains an envelope with HBV surface antigen, and a nucleocapsid containing the hepatitis delta-antigen (HDAg) and an RNA genome of 1.75 kilobases (kb). Recently, the genomic RNA from an HDV serially passaged in chimpanzees has been cloned and sequenced in a study which showed that the HDV RNA is a single-stranded circular molecule with properties similar to those of viroid or virusoid. However, it is not known whether serial passages in chimpanzees had altered the properties of human HDV. Here we report the cloning and sequencing of an HDV RNA isolated directly from a patient with acute delta-hepatitis. The sequence showed considerable divergence (11%) from that of the chimpanzee-adapted HDV. Five open reading frames (ORFs) of more than 100 amino acids in both genomic and anti-genomic sense were found. The largest ORF in antigenomic sense, which can code for 214 amino acids, may correspond to the HDAg.